1. Field of the Invention
This invention is directed to a heat resistant suit and more particularly to such a suit including a heat reflective, insulating coverall which forms an outer covering over an inner garment. The inner garment includes an active cooling air circulation system which is fed by a vortex unit integrated into the coverall.
2. Description of the Related Art
Steam generating boilers for electrical power generating plants can reach internal temperatures well in excess of 2000.degree. Fahrenheit, and the surrounding system of supply pipes and conduits routinely reach temperatures of 500.degree. fahrenheit and greater. In the past, when the boiler or surrounding pipe networks needed maintenance or repair, the boiler would be shut down entirely and cooled to a temperature in which workmen could safely operate. Workers could then enter the boiler and/or the surrounding pipe network to perform the needed repairs. The time needed to cool a boiler from the 2000.degree. operating temperature to a temperature safe for workmen to enter can be as long as 24 hours. The total time period from initial shutdown to subsequent start-up after repair can thus involve two or more days even when the repairs themselves may take only a matter of only a few hours to perform. The cost of bringing a steam driven generator off-line in a major power plant can cost upwards of one hundred thousand dollars per day.
When the boilers themselves need repair, there is no choice but to shut them down and wait for them to cool. Previously, boilers were cooled to an inside temperature of 150.degree. Fahrenheit or less to permit workmen to operate inside for extended periods. Furthermore, previously, when the surrounding pipe network is in need of repair, it was standard procedure for the boiler to be shut down so that the pipes can be cooled.
Thus, it would be desirable to be able to perform repair work inside the boilers without requiring them to be cooled to 150.degree. or, alternatively, repair work in the surrounding pipe network while the boiler is still operating, albeit at a reduced combustion level. As previously mentioned, this can necessitate the workmen operating in environments with temperatures in excess of 500.degree. Fahrenheit. In order to work at such a temperature, the workmen must be protected by specially designed, heat resistant suits which often include an active body cooling capability. Furthermore, workmen in such environments are frequently exposed to noxious or poisonous gasses, so that an artificial breathing apparatus must be used as well.
Numerous prior attempts have been made to design a heat resistant suit for use in high temperature environments. One relatively early example of a heat resistant suit with a cooling capability is that of U.S. Pat. No. 2,573,414 to K. Dunn. The Dunn patent teaches an aluminized coverall which reflects heat, and which incorporates an internal cooling manifold through which cooling air is circulated. Heat resistant suits of the type disclosed by Dunn allowed workers limited protection from elevated temperatures for a short time period. However, to be cost effective, workmen must preferably be capable of continuous work for periods of 30 minutes or longer. Such suits were generally not capable of permitting continuous exposure to temperatures in excess of 150.degree. Fahrenheit for such time periods.
Recent advances in fabric technology and experience with cooling system designs have yielded heat resistant suits with greatly enhanced capabilities. For example, U.S. Pat. No. 4,513,452 to P. Phillip Rankin, Sr. et al. discloses a heat resistant suit with an internal vest through which refrigerated air is circulated and directed against the wearer's body. The vest is covered by a suit including a coat and a trousers portion, both of which are made of a heat resistant material. A pipe network is attached externally to the vest, but inside the outer suit to carry the refrigerated air into the leg and feet portions and the arm and hand portions of the suit. A safety bottle is worn about a belt worn inside the suit to provide breathing air for a limited time should an external air compressor fail. Breathing air from the external compressor or the safety bottle is directed to a face mask into which a radio microphone and speaker are built. A safety harness is partially built into the coat and trousers, with these separate sections of the harness being connected together after the suit is put on.
The suit disclosed in the Rankin patent represented a marked improvement over earlier prior art suits in that it allowed a workmen to work continuously for extended periods at the elevated temperatures mentioned earlier. However, a number of disadvantages resulted from the suit construction. To put the suit on, a wearer must first don the cooling vest, then put on the cooling pipe networks, which must be connected to the vest and to the external compressor. Next the belt containing the safety bottle must be put on along with the breathing mask. The boots, trousers, helmet and gloves must then be put on in a preset order and the coat cinched about the trousers. Next the separate safety harness portions must be connected together. The entire process can take several minutes and often requires a second workman to help the wearer in donning the suit. Furthermore, a separate refrigeration source is required which must be positioned outside of the high temperature work area to refrigerate the circulated cooling air and/or the breathing air. The Rankin et al. U.S. Pat. No. 4,513,452 is expressly incorporated herein by reference.
Another example of a temperature regulated garment is U.S. Pat. No. 4,914,752 to Hinson et al., which discloses a multi-layer cooling suit designed to keep toxic substances from reaching the wearer. An externally worn vortex unit attached to an external compressor provides cooling air to the interior of the suit. The Hinson suit is not designed for continuous use at the extreme temperatures found in a boiler environment. The Hinson patent includes a discussion and illustration of the operation of a typical vortex cooling unit, and, accordingly, U.S. Pat. No. 4,914,752 is also expressly incorporated herein by reference.
It is clear then, that a need still exists for a heat resistant suit equipped for continuous operation at extreme temperatures such as those found in industrial boilers and environs. Such a suit should preferably be equipped with a vortex unit instead of an external refrigeration unit for internal cooling of the wearer. The suit should preferably include a one-piece coverall outer garment and an inner cooling garment adapted to circulate cooling air to the wearer. The outer garment should include dedicated and easily accessible storage locations for the vortex tube, a safety bottle, a radio, etc. The suit may be equipped such that breathing air is drawn from the same flow of compressed air as the cooling air and a separate vortex unit can be provided to cool the breathing air. Finally, since workmen in such environments must be capable of being quickly pulled out of the work areas in emergency situations, a safety harness should be integrated with the suit to which a cable can be quickly connected to pull the workman free.